A method and system for preparing diisobutylene from tert-butanol

Abstract

The application relates to a method and system for preparing diisobutene from tert-butyl alcohol, and belongs to the technical field of diisobutene preparation. The system for preparing diisobutene from tert-butyl alcohol comprises a tert-butyl alcohol reaction assembly for generating isobutene, an isobutene reaction assembly for generating diisobutene, which is connected with the tert-butyl alcohol reaction assembly, a water washing tower for separating unreacted tert-butyl alcohol in the diisobutene, which is connected with the tert-butyl alcohol reaction assembly and the isobutene reaction assembly respectively, and a first tert-butyl alcohol catalytic distillation tower for generating isobutene, which is connected with the water washing tower. The embodiment of the application couples the tert-butyl alcohol dehydration reaction for generating isobutene and the isobutene dimerization for generating diisobutene into one system, has the advantages of less process devices, improved conversion rates of the tert-butyl alcohol and the isobutene and selectivity of diisobutene products, reduced wastewater generation amount, good operation stability, low energy consumption and a simple process flow.

Description

Technical Field

[0001] This application relates to the field of diisobutylene preparation technology, and in particular to a method and system for preparing diisobutylene from tert-butanol. Background Technology

[0002] tert-butanol and isobutylene are important fine chemical raw materials. Tert-butanol is mainly synthesized by hydration of isobutylene in C4 mixtures or as a byproduct of the propylene oxide system. The main methods for preparing isobutylene are the methyl tert-butyl ether hydrolysis method and the tert-butanol dehydration method. Diisobutylene is mainly produced by isobutylene dimerization.

[0003] Currently, the production of diisobutylene involves first dehydrating tert-butanol to produce isobutylene, then dimerizing the isobutylene to produce diisobutylene. This separates isobutylene and diisobutylene into two systems. The existing tert-butanol dehydration system includes two catalytic distillation columns, two water washing columns, and three rectification columns, while the isobutylene condensation system includes three reactors, one catalytic distillation column, and two rectification columns. This two-system process results in a complex production process for diisobutylene, a large number of devices, and high system energy consumption. The conversion rates of tert-butanol and isobutylene, as well as the selectivity of diisobutylene, are relatively low, and other inhibitors need to be introduced. Furthermore, the tert-butanol dehydration system generates a large amount of wastewater. Summary of the Invention

[0004] This application provides a method and system for preparing diisobutylene from tert-butanol to solve the following technical problem: providing a system for preparing diisobutylene from tert-butanol.

[0005] In a first aspect, embodiments of this application provide a system for preparing diisobutylene from tert-butanol, the system comprising:

[0006] tert-butanol reaction assembly 1, used to generate isobutene;

[0007] Isobutylene reaction assembly 2, used to generate diisobutylene, is connected to the tert-butanol reaction assembly 1;

[0008] The water washing tower 3 is used to separate unreacted tert-butanol from diisobutylene and is connected to the tert-butanol reaction assembly 1 and the isobutylene reaction assembly 2, respectively.

[0009] The first tert-butanol catalytic distillation column 4, used to generate isobutene, is connected to the water washing column 3.

[0010] Optionally, the tert-butanol reaction assembly 1 includes:

[0011] tert-butanol refining tower 11;

[0012] The second tert-butanol catalytic distillation column 12 is connected to the tert-butanol refining column 11, the isobutene reaction assembly 2, and the water washing column 3, respectively.

[0013] Optionally, the isobutylene reaction assembly 2 includes:

[0014] Reactor 21 is connected to the second tert-butanol catalytic distillation column 12;

[0015] The isobutylene catalytic distillation column 22 is connected to the water washing column 3 and the reactor 21, respectively.

[0016] Optionally, the top of the second tert-butanol catalytic distillation column 12 is provided with a condenser 121 and a reflux tank 122. The condenser 121, the second tert-butanol catalytic distillation column 12, and the reflux tank 122 form a circulating loop. The aqueous phase outlet of the reflux tank 122 is connected to the second tert-butanol catalytic distillation column 12, the oil phase outlet of the reflux tank 122 is connected to the reactor 21, and the feed inlet of the reflux tank 122 is connected to the isobutylene catalytic distillation column 22.

[0017] Optionally, the system further includes:

[0018] Diisobutylene refining tower 5 is connected to the water washing tower 3;

[0019] Isobutylene refining column 6 is connected to the first tert-butanol catalytic distillation column 4;

[0020] Wastewater recovery tower 7 is connected to the first tert-butanol catalytic distillation tower 4.

[0021] Optionally, the top of the first tert-butanol catalytic distillation column 4 is provided with a condenser 41 and a reflux tank 42. The condenser 41, the first tert-butanol catalytic distillation column 4 and the reflux tank 42 form a circulating loop connection. The aqueous phase outlet of the reflux tank 42 is connected to the wastewater recovery column 7, and the oil phase outlet of the reflux tank 42 is connected to the isobutylene refining column 6.

[0022] In a second aspect, embodiments of this application provide a method for preparing diisobutylene from tert-butanol, adapted to the system described in any one of the first aspects, the method comprising:

[0023] The tert-butanol was subjected to a first dehydration reaction-distillation to obtain isobutylene containing unreacted tert-butanol and water, respectively.

[0024] An inert component and the isobutylene containing unreacted tert-butanol are mixed to carry out a chemical reaction to obtain diisobutylene containing unreacted tert-butanol.

[0025] The diisobutylene containing unreacted tert-butanol was washed with the water to obtain crude diisobutylene and a washing solution containing the tert-butanol.

[0026] The washing solution containing the tert-butanol was subjected to a second dehydration reaction—distillation—to obtain isobutylene and wastewater, respectively.

[0027] Optionally, the first dehydration reaction-distillation of tert-butanol to obtain isobutylene containing unreacted tert-butanol and water includes:

[0028] The tert-butanol was first purified.

[0029] The first purified tert-butanol was subjected to a first dehydration reaction-distillation to obtain isobutylene containing unreacted tert-butanol and water, respectively.

[0030] The process parameters for the first refining process include: operating pressure of 0.05 MPa to 0.08 MPa and operating temperature of 70°C to 105°C.

[0031] The process parameters for the first dehydration reaction-distillation include: operating pressure of 0.3 MPa to 0.4 MPa and operating temperature of 120°C to 150°C.

[0032] Optionally, the chemical reaction includes a dimerization reaction and a dimerization catalytic reaction in sequence;

[0033] The process parameters for the dimerization reaction include: operating pressure of 0.75 MPa to 1.1 MPa and operating temperature of 50°C to 80°C.

[0034] The process parameters for the dimerization catalytic reaction include: operating pressure of 0.45 MPa to 0.55 MPa and operating temperature of 50°C to 170°C.

[0035] Optionally, the process parameters for the water washing include: operating pressure of 0.4 MPa to 0.7 MPa, and operating temperature of 30°C to 40°C; and / or,

[0036] The process parameters for the second dehydration reaction-distillation include: operating pressure of 0.3 MPa to 0.4 MPa and operating temperature of 115°C to 150°C.

[0037] Optionally, the step of washing the diisobutylene containing unreacted tert-butanol with water to obtain crude diisobutylene and a washing solution containing the tert-butanol further includes:

[0038] The crude diisobutylene is then subjected to a second purification process to obtain purified diisobutylene; wherein...

[0039] The process parameters for the second refining process include: operating pressure of 0.05MPa to 0.08MPa and operating temperature of 70℃ to 165℃.

[0040] Optionally, the step of dehydrating the washing solution containing the tert-butanol to obtain isobutylene and wastewater further includes:

[0041] The isobutylene undergoes a third purification process for recycling, and the wastewater is recovered for recycling; wherein,

[0042] The process parameters for the third refining process include: operating pressure of 0.45 MPa to 0.55 MPa, and operating temperature of 50°C to 70°C; and / or,

[0043] The recovery process parameters include: operating pressure 0.05MPa~0.1MPa, and operating temperature 60℃~125℃.

[0044] The technical solutions provided in this application have the following advantages compared with the prior art:

[0045] The system for preparing diisobutylene from tert-butanol provided in this application embodiment comprises a tert-butanol reaction assembly for generating isobutylene and an isobutylene reaction assembly for generating diisobutylene, coupled into a single system. The coupled system has a smooth process flow and requires fewer process devices. The chemical reaction for generating isobutylene in the tert-butanol reaction assembly is a reversible reaction, resulting in unreacted tert-butanol. This unreacted tert-butanol can act as an inhibitor in the isobutylene reaction assembly, improving the conversion rate of isobutylene and the selectivity of diisobutylene. A water washing tower is used to separate the residual tert-butanol from the diisobutylene. A first tert-butanol catalytic distillation tower further reacts the residual tert-butanol to obtain the by-product isobutylene, thereby improving the conversion rate of tert-butanol. The water washing tower is connected to the tert-butanol reaction assembly, directly utilizing the water generated by the tert-butanol reaction assembly, thus reducing wastewater generation. Attached Figure Description

[0046] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0047] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0048] Figure 1 This application provides a schematic diagram of the structure of a system for preparing diisobutylene from tert-butanol, as shown in the embodiments of the present application; wherein,

[0049] 1-Tert-butanol reaction assembly, 2-Isobutene reaction assembly, 3-Water washing tower, 4-First tert-butanol catalytic distillation tower, 11-Tert-butanol refining tower, 12-Second tert-butanol catalytic distillation tower, 21-Reactor, 22-Isobutene catalytic distillation tower, 5-Diisobutene refining tower, 6-Isobutene refining tower, 7-Wastewater recovery tower; 13-Raw material tert-butanol feed line, 14-Refined tert-butanol line, 15-Second tert-butanol catalytic distillation tower bottom water line, 111-Condenser, 121-Condenser, 122-Return Flow tank, 23-reactor feed line, 24-reactor discharge line, 25-reactor shell discharge line, 26-circulating isobutylene and inert component line, 27-water washing tower feed line, 28-condenser, 31-crude diisobutylene after water washing line, 32-water washing tower bottom line containing tert-butanol, 41-condenser, 42-reflux tank, 51-condenser, 61-wastewater recovery tower feed line, 62-crude isobutylene line, 63-condenser, 64-recycled isobutylene return to the reaction shell line, 71-wastewater line, 72-condenser.

[0050] Figure 2 This is a schematic flowchart of a method for preparing diisobutylene from tert-butanol, provided as an embodiment of this application. Detailed Implementation

[0051] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0052] Various embodiments of this application may exist in the form of a range; it should be understood that the description in the form of a range is merely for convenience and brevity and should not be construed as a hard limitation on the scope of this application; therefore, it should be considered that the range description has specifically disclosed all possible sub-ranges and single numerical values ​​within that range. For example, it should be considered that the range description from 1 to 6 has specifically disclosed sub-ranges such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., and single numbers within the range, such as 1, 2, 3, 4, 5, and 6, regardless of the range. Furthermore, whenever a numerical range is referred to herein, it means including any referenced number (fraction or integer) within the referred range.

[0053] In this application, unless otherwise stated, directional terms such as "upper" and "lower" specifically refer to the drawing directions in the accompanying drawings. Furthermore, in the description of this application, terms such as "comprising" and "including" mean "including but not limited to." In this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. In this document, "and / or" describes the relationship between related objects, indicating that three relationships can exist; for example, A and / or B can represent: A alone, A and B simultaneously, or B alone. A and B can be singular or plural. In this document, "at least one" means one or more, and "more than one" means two or more. "At least one," "at least one of the following," or similar expressions refer to any combination of these items, including any combination of single or plural items. For example, "at least one of a, b, or c" or "at least one of a, b, and c" can both mean: a, b, c, ab (i.e., a and b), ac, bc, or abc, where a, b, and c can be a single or multiple.

[0054] It should be noted that in this application, the terms "upper," "lower," "left," "right," "front," "rear," "top," "bottom," "inner," "outer," "vertical," "horizontal," "lateral," and "longitudinal" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. These terms are mainly for the purpose of better describing this application and its embodiments, and are not intended to limit the indicated device, element, or component to having a specific orientation, or to be constructed and operated in a specific orientation.

[0055] Furthermore, in addition to indicating location or positional relationship, some of the aforementioned terms may also have other meanings. For example, the term "above" may also be used in some cases to indicate a certain dependency or connection relationship. Those skilled in the art can understand the specific meaning of these terms in this application based on the specific circumstances.

[0056] Furthermore, the terms "installation," "setup," "equipped with," "connection," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral structure; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium, or an internal connection between two devices, components, or parts. Those skilled in the art can understand the specific meaning of these terms in this application based on the specific circumstances.

[0057] Unless otherwise specified, all raw materials, reagents, instruments and devices used in this application are available on the market or can be prepared by existing methods.

[0058] In a first aspect, embodiments of this application provide a system for preparing diisobutylene from tert-butanol. Figure 1 A schematic diagram of a system for preparing diisobutylene from tert-butanol provided in this application embodiment; please refer to... Figure 1 The system includes:

[0059] tert-butanol reaction assembly 1, used to generate isobutene;

[0060] Isobutylene reaction assembly 2, used to generate diisobutylene, is connected to the tert-butanol reaction assembly 1;

[0061] The water washing tower 3 is used to separate unreacted tert-butanol from diisobutylene and is connected to the tert-butanol reaction assembly 1 and the isobutylene reaction assembly 2, respectively.

[0062] The first tert-butanol catalytic distillation column 4, used to generate isobutene, is connected to the water washing column 3.

[0063] tert-Butanol Reaction Component 1: Its main function is to convert tert-butanol into isobutylene, which is the primary source of isobutylene in the entire system. Controlling the conversion rate of tert-butanol in Component 1, with unreacted tert-butanol acting as an inhibitor, ensures the isobutylene dimerization reaction and improves the selectivity of diisobutylene. Isobutylene Reaction Component 2: Connected to Component 1, it utilizes the isobutylene generated therefrom to further react and generate diisobutylene, thus realizing the conversion process from tert-butanol to diisobutylene. Water Washing Tower 3: Connected to both tert-butanol Reaction Component 1 and Isobutylene Reaction Component 2, its function is to separate unreacted tert-butanol from diisobutylene through water washing extraction, thus purifying the product. First Tert-Butanol Catalytic Distillation Tower 4: Connected to Water Washing Tower 3, it further reacts the residual tert-butanol separated from the water washing tower, converting it into the by-product isobutylene, improving the conversion rate of tert-butanol and achieving efficient resource utilization.

[0064] High process integration: The tert-butanol reaction unit for isobutylene and the isobutylene reaction unit for diisobutylene are coupled into a single system, making the process flow smoother, reducing intermediate steps and equipment, lowering equipment investment and floor space, and improving production efficiency. Increased conversion rate: Unreacted tert-butanol in the tert-butanol reaction unit enters the isobutylene reaction unit, acting as an inhibitor, which helps improve the conversion rate of diisobutylene, making full use of raw materials and reducing waste. Resource recycling: The water washing tower is connected to the tert-butanol reaction unit, directly utilizing the water produced by the tert-butanol reaction unit for the water washing and extraction process, reducing the use of fresh water and wastewater generation. Improved product quality: The water washing tower separates residual tert-butanol from diisobutylene, and the first tert-butanol catalytic distillation tower further treats the residual tert-butanol, improving the purity of the diisobutylene product and obtaining isobutylene as a byproduct, increasing the added value of the product.

[0065] The tert-butanol reaction assembly 1 is used to generate isobutylene, and the isobutylene reaction assembly 2 is used to generate diisobutylene, which are coupled into a system. The coupled system has a smooth process flow and fewer process devices. The water washing tower 3 is used to separate unreacted tert-butanol and is connected to the tert-butanol reaction assembly 1 and the isobutylene reaction assembly 2 respectively. In the tert-butanol reaction assembly 1, while generating isobutylene, there is also unreacted tert-butanol and water. The isobutylene enters the isobutylene reaction assembly 2 to obtain diisobutylene containing unreacted tert-butanol. Thus, the water washing tower 3 separates the mixture of tert-butanol and water. The mixture of tert-butanol and water enters the first tert-butanol catalytic distillation tower 4 to produce isobutylene as a by-product, thereby improving the conversion rate of tert-butanol and reducing the amount of wastewater generated.

[0066] Washing tower 3 is a sieve plate tower, used to extract tert-butanol from diisobutylene using water. The extraction water is generated from the dehydration reaction of tert-butanol, reducing wastewater discharge. A sieve plate tower is a type of plate tower containing several layers of horizontal sieve plates with numerous evenly distributed sieve holes. Under gravity, the liquid flows from top to bottom through each sieve plate, forming a liquid layer of a certain thickness on the sieve plates. Both the upper and lower feeds are liquid; diisobutylene (from bottom to top) is the dispersed phase, and water (from top to bottom) is the continuous phase. The dispersed phase, driven by the pressure difference, passes through the sieve holes from bottom to top, ensuring full contact with the liquid layer for mass and heat transfer. During the extraction process, water is added as the extractant from the top of the tower, while the diisobutylene-tert-butanol mixture is added from a specific location within the tower. As the continuous aqueous phase flows downward, it comes into full contact with the rising diisobutylene dispersed phase. Since the solubility of tert-butanol in water is greater than its solubility in diisobutylene, tert-butanol will gradually transfer from diisobutylene to the aqueous phase, thereby achieving the separation of diisobutylene and tert-butanol.

[0067] The first tert-butanol catalytic distillation column 4 dehydrates a small portion of unreacted tert-butanol into isobutene.

[0068] In some embodiments, the tert-butanol reaction assembly 1 includes:

[0069] tert-butanol refining tower 11;

[0070] The second tert-butanol catalytic distillation column 12 is connected to the tert-butanol refining column 11, the isobutene reaction assembly 2, and the water washing column, respectively.

[0071] After purification, tert-butanol enters the second tert-butanol catalytic distillation column 12. The purified tert-butanol is more conducive to conversion. A small amount of unconverted tert-butanol is further converted in the first tert-butanol catalytic distillation column, which improves the conversion rate of tert-butanol. The second tert-butanol catalytic distillation column 12 dehydrates most of the 80%–98% tert-butanol in the feed to isobutylene.

[0072] In some embodiments, the isobutylene reaction assembly 2 includes:

[0073] Reactor 21 is connected to the second tert-butanol catalytic distillation column 12;

[0074] The isobutylene catalytic distillation column 22 is connected to the water washing column 3 and the reactor 21, respectively.

[0075] Reactor 21 is a tubular reactor. Most of the isobutylene dimers within reactor 21 to form diisobutylene. The unreacted isobutylene is further dimerized in the presence of a catalyst in the isobutylene catalytic distillation column to form diisobutylene. The unreacted isobutylene then re-enters reactor 21 from the outlet of the isobutylene catalytic distillation column 22 to undergo another chemical reaction, producing diisobutylene and thus increasing the isobutylene conversion rate.

[0076] In some embodiments, the system further includes:

[0077] Diisobutylene refining tower 5 is connected to the water washing tower 3;

[0078] Isobutylene refining column 6 is connected to the first tert-butanol catalytic distillation column 4;

[0079] Wastewater recovery tower 7 is connected to the first tert-butanol catalytic distillation tower 4.

[0080] Diisobutylene refining column 5 receives crude diisobutylene obtained from the isobutylene catalytic distillation column 22. This crude diisobutylene is washed with water generated from the dehydration reaction of the second tert-butanol and then fed into the diisobutylene refining column 5. The refined diisobutylene is then drawn off via a side stream. Isobutylene refining column 6 receives isobutylene and water from the dehydration reaction of the first tert-butanol catalytic distillation column 4. Crude isobutylene is sent to the isobutylene refining column 6, while a portion of the refined isobutylene is collected and partially cooled in the shell of reactor 21 before entering the isobutylene catalytic distillation column 22. Reactor 21 uses the raw material isobutylene to cool the reactants, ensuring that reactor 21 does not overheat, improving the selectivity of diisobutylene, and reducing energy consumption. Feeding the heated isobutylene into the isobutylene catalytic distillation column 22 saves on cooling water consumption in reactor 21 and reduces steam consumption in the isobutylene catalytic distillation column 22. Wastewater recovery tower 7 is used to recover wastewater generated from the first tert-butanol catalytic distillation tower 4 before it is discharged.

[0081] In addition, the second tert-butanol catalytic distillation column 12, the first tert-butanol catalytic distillation column 4, and the isobutene catalytic distillation column 22 are all equipped with macroporous strong acid cation exchange resins as catalysts.

[0082] In some embodiments, a condenser 121 and a reflux tank 122 are provided at the top of the second tert-butanol catalytic distillation column 12. The condenser 121, the second tert-butanol catalytic distillation column 12, and the reflux tank 122 form a circulating loop. The aqueous phase outlet of the reflux tank 122 is connected to the second tert-butanol catalytic distillation column 12, the oil phase outlet of the reflux tank 122 is connected to the reactor 21, and the feed inlet of the reflux tank 122 is connected to the isobutylene catalytic distillation column 22.

[0083] In some embodiments, the top of the first tert-butanol catalytic distillation column 4 is provided with a condenser 41 and a reflux tank 42. The condenser 41, the first tert-butanol catalytic distillation column 4 and the reflux tank 42 form a circulating loop connection. The aqueous phase outlet of the reflux tank 42 is connected to the wastewater recovery column 7, and the oil phase outlet of the reflux tank 42 is connected to the isobutylene refining column 6.

[0084] For example, the system for preparing diisobutylene from tert-butanol includes a reactor 21, three catalytic distillation columns (second tert-butanol catalytic distillation column 12, first tert-butanol catalytic distillation column 4 and isobutylene catalytic distillation column 22), a water washing column 3, three purification columns (tert-butanol purification column 11, diisobutylene purification column 5 and isobutylene purification column 6) and a recovery column (wastewater recovery column 7), with a condenser installed at the top of each column. tert-Butanol is fed into tert-butanol refining tower 11 via feed line 13. After refining, tert-butanol feed line 14 enters the second tert-butanol catalytic distillation tower 12 for dehydration and distillation, yielding isobutylene and water. Isobutylene and inert components are fed into reactor 21 via feed line 23 to react and generate diisobutylene. Diisobutylene, inert components, and unreacted isobutylene are fed into isobutylene catalytic distillation tower 22 via discharge line 24. Unreacted isobutylene and inert components are recycled via recycling line 26. Crude diisobutylene is fed into the water washing tower via feed line 27. The water in the water washing tower comes from the water generated by the tert-butanol dehydration reaction in the second tert-butanol catalytic distillation tower 12. The bottom of diisobutylene from column 2 enters the top of column 3 via bottom water line 15 of the second tert-butanol catalytic distillation column for washing. After washing, crude diisobutylene enters diisobutylene refining column 5 via line 31. Refined diisobutylene is extracted via a side line. The water containing tert-butanol after washing enters the first tert-butanol catalytic distillation column 4 via bottom tert-butanol line 32 of the washing column for dehydration and distillation again, yielding isobutylene and water respectively. Isobutylene is sent to isobutylene refining column 6 via crude isobutylene line 62. Part of the refined isobutylene is collected, and part enters the shell of reactor 21 via the refined isobutylene return reaction shell line 64 for cooling and use. Then, it enters the isobutylene catalytic distillation column 22 via the reactor shell discharge line 25 for reaction. Wastewater is sent to wastewater recovery column 7 via wastewater recovery column feed line 61 for recovery and discharge.

[0085] The top of the first tert-butanol catalytic distillation column 4 is equipped with a condenser 41 and a reflux tank 42. The reflux tank 42 is connected to the wastewater recovery tower 7. The condenser 41, the first tert-butanol catalytic distillation column 4, and the reflux tank 42 form a circulating loop. The reflux tank 42 is connected to the isobutylene refining column 6 and the wastewater recovery tower 7, respectively. The reflux tank 42 includes an aqueous phase and an isobutylene oil phase, forming upper and lower layers. The reflux tank 42 has an oil phase outlet and an aqueous phase outlet. The aqueous phase enters the wastewater recovery tower 7 through the wastewater recovery tower feed line 61, and the isobutylene oil phase enters the isobutylene refining tower 6 through the coarse isobutylene line 62. The water generated by the dehydration reaction in the first tert-butanol catalytic distillation column 4 is discharged through the wastewater line 71.

[0086] The second tert-butanol catalytic distillation column 12 is equipped with a condenser 121 and a reflux tank 122 at its top. The second tert-butanol catalytic distillation column 12, condenser 121, and reflux tank 122 form a circulation loop. The reflux tank 122 contains an aqueous phase containing tert-butanol and an oil phase containing tert-butanol, isobutylene, and inert components, forming upper and lower stratification. The reflux tank 122 has an oil phase outlet and an aqueous phase outlet. The aqueous phase containing tert-butanol continues to return to the second tert-butanol catalytic distillation column 12 through the aqueous phase outlet, while the oil phase containing tert-butanol, isobutylene, and inert components enters the reactor 21, thus maximizing the utilization rate of tert-butanol. The inert components are directly fed into the reflux tank 122. Unreacted isobutylene and inert components in the isobutylene catalytic distillation column 22 are liquefied through the condenser 28 from the top outlet of the isobutylene catalytic distillation column 22 and returned to the reflux tank 122 to continue being fed into the reactor 21 for reaction. The isobutylene catalytic distillation column 22 is connected to the reflux tank 122.

[0087] In addition, a condenser 111 is installed at the top of the tert-butanol refining tower 11, a condenser 72 is installed at the top of the wastewater recovery tower 7, a condenser 51 is installed at the top of the diisobutylene refining tower 5, and a condenser 63 is installed at the top of the isobutylene refining tower 6.

[0088] The system for preparing diisobutylene from tert-butanol provided in this application has the following advantages, including:

[0089] 1. The conversion of tert-butanol to diisobutylene involves coupling the dehydration reaction of tert-butanol to produce isobutylene and the dimerization of isobutylene to produce diisobutylene into a single system. The coupled system has a smooth process flow and requires fewer process devices. Isobutylene is used to remove the heat of reaction of isobutylene dimerization. The gasified isobutylene is then sent to an isobutylene catalytic distillation column, which reduces the system's steam consumption and energy consumption. The process is simple to operate and also produces isobutylene as a byproduct.

[0090] 2. By using the tert-butanol to diisobutylene conversion system, the conversion rates of tert-butanol and isobutylene are increased, and the selectivity of diisobutylene is also increased. At the same time, it is not necessary to introduce demineralized water into the tert-butanol dehydration reaction tower or to introduce inhibitors into the reactor, thereby reducing the wastewater discharge of the tert-butanol to diisobutylene conversion system.

[0091] Secondly, embodiments of this application provide a method for preparing diisobutylene from tert-butanol, adapted to the system described in any one of the first aspects. Figure 2 A schematic flowchart illustrating a method for preparing diisobutylene from tert-butanol, provided in an embodiment of this application; please refer to [link / reference]. Figure 2 The method includes:

[0092] S1. The tert-butanol is subjected to a first dehydration reaction-distillation to obtain isobutylene containing unreacted tert-butanol and water, respectively.

[0093] tert-butanol undergoes a first dehydration reaction—distillation. Under specific conditions, tert-butanol undergoes a dehydration reaction to produce isobutylene and water. Distillation separates the isobutylene, tert-butanol, and water by utilizing the difference in their boiling points.

[0094] In some embodiments, the first dehydration reaction-distillation of tert-butanol to obtain isobutylene containing unreacted tert-butanol and water includes:

[0095] The tert-butanol was first purified.

[0096] The first purified tert-butanol was subjected to a first dehydration reaction-distillation to obtain isobutylene containing unreacted tert-butanol and water, respectively.

[0097] The process parameters for the first refining process include: operating pressure of 0.05 MPa to 0.08 MPa and operating temperature of 70°C to 105°C.

[0098] The process parameters for the first dehydration reaction-distillation include: operating pressure of 0.3 MPa to 0.4 MPa and operating temperature of 120 to 150 °C.

[0099] The purpose of the first purification step is to pre-treat tert-butanol, removing any impurities and increasing its purity. This creates more favorable conditions for subsequent dehydration reactions, improving reaction efficiency and product quality. The operating pressure can be 0.05 MPa to 0.08 MPa, and the operating temperature can be 70°C to 105°C. The difference in physical properties (such as boiling point and volatility) between tert-butanol and impurities is utilized to separate the impurities through methods such as distillation. Lower operating pressure helps reduce the boiling point of tert-butanol, minimizing side reactions such as decomposition and polymerization during purification. A suitable operating temperature ensures that tert-butanol remains in a liquid state, facilitating separation from impurities. For example, in the first purification step, the operating pressure can be 0.05 MPa, 0.06 MPa, 0.07 MPa, 0.08 MPa, etc.; and the operating temperature can be 70°C, 75°C, 80°C, 85°C, 90°C, 95°C, 100°C, 105°C, etc.

[0100] The operating pressure for the first dehydration reaction-distillation can be 0.3 MPa to 0.4 MPa, and the operating temperature can be 120°C to 150°C. At higher operating pressures and temperatures, the hydroxyl group within the tert-butanol molecule undergoes an elimination reaction with the hydrogen atom on the adjacent carbon atom, producing isobutylene and water. Distillation separates isobutylene, tert-butanol, and water based on their different boiling points. For example, in the first dehydration reaction-distillation, the operating pressure can be 0.3 MPa, 0.35 MPa, 0.4 MPa, etc.; and the operating temperature can be 120°C, 125°C, 130°C, 135°C, 140°C, 145°C, 150°C, etc.

[0101] S2. The inert component and the isobutylene containing unreacted tert-butanol are mixed to carry out a chemical reaction to obtain diisobutylene containing unreacted tert-butanol.

[0102] The inert component can be one or a combination of isobutane and n-butane, which can prevent overheating of the reaction and dilution of isobutene; unreacted tert-butanol can act as an inhibitor to reduce the probability of trimerization and tetramerization, thereby improving the selectivity and formation rate of diisobutene.

[0103] In some embodiments, the chemical reaction comprises, in sequence, a dimerization reaction and a dimerization catalytic reaction;

[0104] The process parameters for the dimerization reaction include: operating pressure of 0.75 MPa to 1.1 MPa and operating temperature of 50°C to 80°C.

[0105] The process parameters for the dimerization catalytic reaction include: operating pressure of 0.45 MPa to 0.55 MPa and operating temperature of 50°C to 170°C.

[0106] Isobutylene containing unreacted tert-butanol is mixed with an inert component to undergo a chemical reaction consisting of a dimerization reaction and a dimerization catalytic reaction, thereby fully converting isobutylene into diisobutylene and improving the isobutylene conversion rate. The isobutylene containing unreacted tert-butanol undergoes a dimerization reaction under specific conditions. The operating pressure can be 0.75 MPa to 1.1 MPa, and the operating temperature can be 50°C to 80°C. Under these pressure and temperature conditions, an addition reaction occurs between isobutylene molecules, and two isobutylene molecules combine to form a dimer. Higher pressure increases the collision frequency of reactant molecules, promoting the reaction; a suitable temperature range ensures sufficient activation energy while avoiding an increase in side reactions due to excessively high temperatures. For example, in the dimerization reaction, the operating pressure can be 0.75 MPa, 0.8 MPa, 0.9 MPa, 1.0 MPa, 1.1 MPa, etc.; and the operating temperature can be 50°C, 60°C, 70°C, 80°C, etc.

[0107] The product after the dimerization reaction can undergo a further dimerization catalytic reaction at an operating pressure of 0.45 MPa to 0.55 MPa and an operating temperature of 50°C to 170°C to continuously generate diisobutylene and improve the conversion rate of isobutylene. For example, in the dimerization catalytic reaction, the operating pressure can be 0.45 MPa, 0.55 MPa, etc.; and the operating temperature can be 50°C, 60°C, 70°C, 80°C, 90°C, 100°C, 110°C, 120°C, 130°C, 140°C, 150°C, 160°C, 170°C, etc.

[0108] S3. The diisobutylene containing unreacted tert-butanol is washed with the water to obtain crude diisobutylene and a washing solution containing the tert-butanol.

[0109] tert-butanol is somewhat water-soluble, while diisobutylene is insoluble in water. By washing with water, tert-butanol dissolves in the water, thus separating tert-butanol and diisobutylene. The tert-butanol in the diisobutylene is extracted with water, and the extraction water is the water generated from the dehydration reaction of tert-butanol, reducing wastewater discharge.

[0110] In some embodiments, the step of washing the diisobutylene containing unreacted tert-butanol with water to obtain crude diisobutylene and a washing solution containing the tert-butanol further includes:

[0111] The crude diisobutylene is then subjected to a second purification process to obtain purified diisobutylene; wherein...

[0112] The process parameters for the second refining process include: operating pressure of 0.05MPa to 0.08MPa and operating temperature of 70℃ to 165℃.

[0113] After obtaining crude diisobutylene and a washing solution containing tert-butanol through water washing, a second purification step is added to further improve the purity of diisobutylene and obtain a purified diisobutylene product that meets higher quality requirements to satisfy the application needs of different fields. The water washing operation utilizes the water solubility of tert-butanol, mixing the diisobutylene containing unreacted tert-butanol with water to dissolve the tert-butanol, thus achieving preliminary separation of tert-butanol and diisobutylene, yielding crude diisobutylene and a washing solution containing tert-butanol. The crude diisobutylene undergoes a second purification process, with an operating pressure of 0.05 MPa to 0.08 MPa and an operating temperature of 70℃ to 165℃, to remove light and heavy components from the crude diisobutylene, obtaining diisobutylene with a purity of over 99.5%. For example, the operating pressure can be 0.05MPa, 0.06MPa, 0.07MPa, 0.08MPa, etc.; the operating temperature can be 70℃, 80℃, 90℃, 100℃, 110℃, 120℃, 130℃, 140℃, 150℃, 160℃, 165℃, etc.

[0114] S4. The washing solution containing the tert-butanol is subjected to a second dehydration reaction-distillation to obtain isobutylene and wastewater, respectively.

[0115] The tert-butanol in the washing solution undergoes a dehydration reaction again to produce isobutylene and water, and the isobutylene and wastewater are separated by distillation.

[0116] In some embodiments, the process parameters for the water washing include: operating pressure of 0.4 MPa to 0.7 MPa, and operating temperature of 30°C to 40°C; and / or,

[0117] The process parameters for the second dehydration reaction-distillation include: operating pressure of 0.3 MPa to 0.4 MPa and operating temperature of 115°C to 150°C.

[0118] During water washing, the operating pressure can be 0.4 MPa to 0.7 MPa, and the operating temperature can be 30℃ to 40℃. Appropriate pressure ensures good solubility of tert-butanol in water, while also minimizing the miscibility of diisobutylene and water, which is beneficial for the separation of the extract phase and the raffinate phase. It also reduces energy consumption because near-room temperature eliminates the need for extensive additional heating or cooling. For example, during water washing, the operating pressure can be 0.4 MPa, 0.5 MPa, 0.6 MPa, 0.7 MPa, etc.; and the operating temperature can be 30℃, 32℃, 34℃, 36℃, 38℃, 40℃, etc. In the second dehydration reaction—distillation—the operating pressure can be 0.3 MPa to 0.4 MPa, and the operating temperature can be 115℃ to 150℃, causing tert-butanol to undergo a dehydration reaction to produce isobutylene and water. Simultaneously, it facilitates the separation of isobutylene and wastewater by distillation. A suitable temperature provides sufficient energy for the smooth progress of the tert-butanol dehydration reaction while also meeting the requirements for distillation separation. For example, the operating pressure can be 0.3 MPa, 0.35 MPa, 0.4 MPa, etc.; and the operating temperature can be 115℃, 120℃, 125℃, 130℃, 135℃, 140℃, 145℃, 150℃, etc.

[0119] In some embodiments, the step of dehydrating the washing solution containing the tert-butanol to obtain isobutylene and wastewater further includes:

[0120] The isobutylene undergoes a third purification process for recycling, and the wastewater is recovered for recycling; wherein,

[0121] The process parameters for the third refining process include: operating pressure of 0.45 MPa to 0.55 MPa and operating temperature of 50°C to 70°C.

[0122] The recovery process parameters include: operating pressure 0.05MPa~0.1MPa, and operating temperature 60℃~125℃.

[0123] After the washing solution containing tert-butanol undergoes a second dehydration reaction-distillation to obtain isobutylene and wastewater, a third purification and wastewater recovery step is added. The aim is to further improve the purity of isobutylene, allowing it to be recycled into the reaction, while simultaneously treating and recovering the wastewater, reducing resource waste and environmental pollution. In the third purification step, the operating pressure can be 0.45 MPa–0.55 MPa, and the operating temperature can be 50℃–70℃, resulting in the removal of heavy components from the crude isobutylene to obtain isobutylene with a purity of over 99.9%. This improves the utilization rate of raw materials, reduces the amount of tert-butanol input, and lowers production costs. Simultaneously, the purified isobutylene participates in the reaction again, helping to improve the yield and quality of diisobutylene. In the recovery step, the operating pressure can be 0.05 MPa.

[0124] The system operates at pressures ranging from 0.1 MPa to 60°C to 125°C, removing impurities from wastewater and allowing for water recycling. This reduces water waste and environmental pollution. For example, in the third refining process, the operating pressure can be 0.45 MPa, 0.48 MPa, 0.5 MPa, 0.53 MPa, or 0.55 MPa; and the operating temperature can be 50°C, 55°C, 60°C, 65°C, or 70°C. In the recovery process, the operating pressure can be 0.05 MPa, 0.06 MPa, 0.07 MPa, 0.08 MPa, 0.09 MPa, or 0.1 MPa; and the operating temperature can be 60°C, 70°C, 80°C, 90°C, 100°C, 110°C, 120°C, or 125°C.

[0125] The method for preparing diisobutylene from tert-butanol is based on the system for preparing diisobutylene from tert-butanol described above. The specific components of the system for preparing diisobutylene from tert-butanol can be referred to in the above embodiments. Since the method for preparing diisobutylene from tert-butanol adopts some or all of the technical solutions of the above embodiments, it has at least all the beneficial effects brought about by the technical solutions of the above embodiments, which will not be elaborated here.

[0126] The present application is further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the application. Experimental methods in the following embodiments that do not specify specific conditions are generally determined according to national standards. If there is no corresponding national standard, then generally accepted international standards, conventional conditions, or conditions recommended by the manufacturer are followed.

[0127] Each embodiment uses the macroporous cation exchange resin catalyst with the product technical indicators listed in Table 1 as the implementation catalyst for the implementation description, but the protection scope of the embodiments of this application is not limited to the following catalysts.

[0128] Table 1

[0129] Moisture content % 16～60 Mass exchange capacity mmol / g 2.6～5.5 Wet apparent density g / ml 0.73～0.9 Wet true density (g / ml) 1.15～1.3 Particle size range (0.4 mm to 1.35 mm)% ≥95 strength% ≥95

[0130] Example 1

[0131] The composition and feed of the raw material tert-butanol are shown in Table 2.

[0132] Table 2

[0133]

[0134]

[0135] A method for preparing diisobutylene from tert-butanol, comprising:

[0136] The tert-butanol is subjected to a first purification process; wherein, the first purification process is carried out at an operating pressure of 0.05–0.08 MPa and an operating temperature of 70–105 °C.

[0137] The first purified tert-butanol was subjected to a first dehydration reaction-distillation to obtain isobutylene containing unreacted tert-butanol and water, respectively; wherein, the first dehydration reaction-distillation was carried out at an operating pressure of 0.3-0.4 MPa and an operating temperature of 120-150℃.

[0138] Isobutane and isobutene containing unreacted tert-butanol are mixed to undergo a dimerization reaction and a dimerization catalytic reaction sequentially to obtain diisobutene containing unreacted tert-butanol; wherein, the dimerization reaction is carried out at an operating pressure of 0.75–1.1 MPa and an operating temperature of 50–80 °C; the dimerization catalytic reaction is carried out at an operating pressure of 0.45–0.55 MPa and an operating temperature of 50–170 °C.

[0139] Diisobutylene containing unreacted tert-butanol was washed with water to obtain crude diisobutylene and a washing solution containing tert-butanol; wherein, the water washing was carried out at an operating pressure of 0.4–0.7 MPa and an operating temperature of 30–40 °C.

[0140] The washing solution containing tert-butanol was subjected to a second dehydration reaction-distillation to obtain isobutylene and wastewater, respectively; wherein, the second dehydration reaction-distillation was carried out at an operating pressure of 0.3-0.4 MPa and an operating temperature of 115-150℃.

[0141] Isobutylene undergoes a third purification process for recycling, and wastewater is also recycled. The third purification process involves an operating pressure of 0.45–0.55 MPa and an operating temperature of 50–70 °C. The recycling process involves an operating pressure of 0.05–0.1 MPa and an operating temperature of 60–125 °C.

[0142] The effectiveness of the method for preparing diisobutylene from tert-butanol in Example 1 was evaluated, as shown in Table 3.

[0143] Table 3

[0144] project Example 1 tert-Butanol conversion rate 99.65％ Isobutylene conversion rate 96.42％ Diisobutylene selectivity 97.31％ Wastewater discharge 933kg / hr Demineralized water dosage 0kg / hr Inhibitor dosage 0kg / hr

[0145] Example 2

[0146] The composition and feed of the raw material tert-butanol are shown in Table 4.

[0147] Table 4

[0148] Components mass percentage (wt%) water 10～20 methanol 0.3～0.8 acetone 0.1～0.3 Isopropanol 0.3～0.5 Isobutanol 0.3～0.5 tert-Butanol 80～90 Propylene glycol 0.05～0.1 tert-butyl formate 0.05～0.1 Isobutyl formate 0.03～0.1 Feed rate (kg / hr) 2000

[0149] A method for preparing diisobutylene from tert-butanol, comprising:

[0150] The tert-butanol is subjected to a first purification process; wherein, the first purification process is carried out at an operating pressure of 0.05–0.08 MPa and an operating temperature of 70–105 °C.

[0151] The first purified tert-butanol was subjected to a first dehydration reaction-distillation to obtain isobutylene containing unreacted tert-butanol and water, respectively; wherein, the first dehydration reaction-distillation was carried out at an operating pressure of 0.3-0.4 MPa and an operating temperature of 120-150℃.

[0152] Isobutane and isobutene containing unreacted tert-butanol are mixed to undergo a dimerization reaction and a dimerization catalytic reaction sequentially to obtain diisobutene containing unreacted tert-butanol; wherein, the dimerization reaction is carried out at an operating pressure of 0.75–1.1 MPa and an operating temperature of 50–80 °C; the dimerization catalytic reaction is carried out at an operating pressure of 0.45–0.55 MPa and an operating temperature of 50–170 °C.

[0153] Diisobutylene containing unreacted tert-butanol was washed with water to obtain crude diisobutylene and a washing solution containing tert-butanol; wherein, the water washing was carried out at an operating pressure of 0.4–0.7 MPa and an operating temperature of 30–40 °C.

[0154] The washing solution containing tert-butanol was subjected to a second dehydration reaction-distillation to obtain isobutylene and wastewater, respectively; wherein, the second dehydration reaction-distillation was carried out at an operating pressure of 0.3-0.4 MPa and an operating temperature of 115-150℃.

[0155] Isobutylene undergoes a third purification process for recycling, and wastewater is also recycled. The third purification process involves an operating pressure of 0.45–0.55 MPa and an operating temperature of 50–70 °C. The recycling process involves an operating pressure of 0.05–0.1 MPa and an operating temperature of 60–125 °C.

[0156] The effectiveness of the method for preparing diisobutylene from tert-butanol in Example 2 was evaluated, and please refer to Table 5.

[0157] Table 5

[0158]

[0159]

[0160] In summary, Examples 1 and 2 achieved a tert-butanol conversion rate greater than 99.5%, an isobutylene conversion rate greater than 95%, and a diisobutylene selectivity greater than 95%, thus achieving advantages such as improved tert-butanol and isobutylene conversion rates and diisobutylene product selectivity, reduced wastewater generation, good operational stability, low energy consumption, and a simple process flow.

[0161] One or more technical solutions in the embodiments of this application have at least the following technical effects or advantages:

[0162] (1) The top water of the first tert-butanol catalytic distillation tower, the top water of the water washing tower, and the top water of the second tert-butanol catalytic distillation tower in this system are all recycled water from this system, which reduces the amount of demineralized water used and also reduces the amount of wastewater generated.

[0163] (2) Tert-butanol, after purification, enters the first tert-butanol dehydration reaction tower. The purified tert-butanol is more conducive to conversion. A small amount of unconverted tert-butanol is further converted in the first tert-butanol catalytic distillation tower, which improves the conversion rate of tert-butanol. Isobutylene enters the catalytic distillation tower after passing through the tubular reactor. The reaction section of the catalytic distillation tower is filled with a catalytic distillation module containing an isobutylene composite catalyst. The unreacted isobutylene continues to undergo a dimerization catalytic reaction in the reaction section of the catalytic distillation tower, thereby improving the isobutylene conversion rate.

[0164] (3) The reaction method of using a tubular reactor is adopted. Inert components are mixed in before entering the reactor, and the inert components are mixed and passed through the tubular reactor in one go, which reduces the probability of trimerization and tetramerization, thereby improving the selectivity of diisobutylene.

[0165] (4) The two systems of tert-butanol dehydration and isobutylene superposition are coupled into one system. The number of tower devices in the coupled system is reduced, thereby reducing the energy consumption of the system. At the same time, the reactor uses the raw material isobutylene to cool and remove heat from the reactants, and sends the heated isobutylene into the catalytic distillation tower, which saves the consumption of reactor cooling water and reduces the consumption of steam in the catalytic distillation tower.

[0166] The above description is merely a specific embodiment of this application, enabling those skilled in the art to understand or implement this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A system for preparing diisobutylene from tert-butanol, the system comprising: tert-butanol reaction assembly (1) is used to generate isobutene; Isobutylene reaction assembly (2), used to generate diisobutylene, is connected to the tert-butanol reaction assembly (1); A water washing tower (3) is used to separate unreacted tert-butanol from diisobutylene and is connected to the tert-butanol reaction assembly (1) and the isobutylene reaction assembly (2), respectively. The first tert-butanol catalytic distillation column (4), used to generate isobutylene from unreacted tert-butanol, is connected to the water washing column (3).

2. The system according to claim 1, characterized in that, The tert-butanol reaction assembly (1) includes: tert-butanol refining tower (11); The second tert-butanol catalytic distillation column (12) is connected to the tert-butanol refining column (11), the isobutene reaction assembly (2), and the water washing column (3), respectively.

3. The system according to claim 2, characterized in that, The isobutylene reaction assembly (2) includes: The reactor (21) is connected to the second tert-butanol catalytic distillation column (12); The isobutylene catalytic distillation column (22) is connected to the water washing column (3) and the reactor (21), respectively.

4. The system according to claim 3, characterized in that, The top of the second tert-butanol catalytic distillation column (12) is provided with a condenser (121) and a reflux tank (122). The condenser (121), the second tert-butanol catalytic distillation column (12) and the reflux tank (122) form a circulating loop. The water phase outlet of the reflux tank (122) is connected to the second tert-butanol catalytic distillation column (12), the oil phase outlet of the reflux tank (122) is connected to the reactor (21), and the feed inlet of the reflux tank (122) is connected to the isobutylene catalytic distillation column (22).

5. The system according to claim 1, characterized in that, The system also includes: The diisobutylene refining tower (5) is connected to the water washing tower (3); The isobutylene refining column (6) is connected to the first tert-butanol catalytic distillation column (4); The wastewater recovery tower (7) is connected to the first tert-butanol catalytic distillation tower (4).

6. The system according to claim 5, characterized in that, The top of the first tert-butanol catalytic distillation column (4) is provided with a condenser (41) and a reflux tank (42). The condenser (41), the first tert-butanol catalytic distillation column (4) and the reflux tank (42) form a circulating loop connection. The aqueous phase outlet of the reflux tank (42) is connected to the wastewater recovery tower (7), and the oil phase outlet of the reflux tank (42) is connected to the isobutylene refining tower (6).

7. A method for preparing diisobutylene from tert-butanol, adapted to the system according to any one of claims 1 to 6, the method comprising: The tert-butanol was subjected to a first dehydration reaction-distillation to obtain isobutylene containing unreacted tert-butanol and water, respectively. An inert component and the isobutylene containing unreacted tert-butanol are mixed to carry out a chemical reaction to obtain diisobutylene containing unreacted tert-butanol. The diisobutylene containing unreacted tert-butanol was washed with the water to obtain crude diisobutylene and a washing solution containing the tert-butanol. The washing solution containing the tert-butanol was subjected to a second dehydration reaction—distillation—to obtain isobutylene and wastewater, respectively.

8. The method according to claim 7, characterized in that, The first dehydration reaction-distillation of tert-butanol yields isobutylene containing unreacted tert-butanol and water, comprising: The tert-butanol was first purified. The first purified tert-butanol was subjected to a first dehydration reaction-distillation to obtain isobutylene containing unreacted tert-butanol and water, respectively. The process parameters for the first refining process include: operating pressure of 0.05 MPa to 0.08 MPa and operating temperature of 70°C to 105°C. The process parameters for the first dehydration reaction-distillation include: operating pressure of 0.3 MPa to 0.4 MPa and operating temperature of 120°C to 150°C.

9. The method according to claim 7, characterized in that, The chemical reaction includes, in sequence, a dimerization reaction and a dimerization catalytic reaction; The process parameters for the dimerization reaction include: operating pressure of 0.75 MPa to 1.1 MPa and operating temperature of 50°C to 80°C. The process parameters for the dimerization catalytic reaction include: operating pressure of 0.45 MPa to 0.55 MPa and operating temperature of 50°C to 170°C.

10. The method according to claim 7, characterized in that, The process parameters for the water washing include: operating pressure of 0.4 MPa to 0.7 MPa, and operating temperature of 30°C to 40°C; and / or, The process parameters for the second dehydration reaction-distillation include: operating pressure of 0.3 MPa to 0.4 MPa and operating temperature of 115°C to 150°C.

11. The method according to claim 7, characterized in that, The process of washing the diisobutylene containing unreacted tert-butanol with water to obtain crude diisobutylene and a washing solution containing the tert-butanol further includes: The crude diisobutylene is then subjected to a second purification process to obtain purified diisobutylene; wherein... The process parameters for the second refining process include: operating pressure of 0.05MPa to 0.08MPa and operating temperature of 70℃ to 165℃.

12. The method according to claim 7, characterized in that, The step of dehydrating the washing solution containing tert-butanol to obtain isobutene and wastewater further includes: The isobutylene undergoes a third purification process for recycling, and the wastewater is recovered for recycling; wherein, The process parameters for the third refining process include: operating pressure of 0.45 MPa to 0.55 MPa, and operating temperature of 50°C to 70°C; and / or, The recovery process parameters include: operating pressure 0.05MPa~0.1MPa, and operating temperature 60℃~125℃.

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